ES2227982T3 - HIGH FREQUENCY TRANSMISSION CABLE WITH TWO DRIVER GROUPS. - Google Patents

Abstract

THE CABLE PRESENTS A SLIDING (84) OF A MAINTENANCE HOSE (8) SITUATED LONGITUDINALLY BETWEEN TWO GROUPS OF ELECTRIC DRIVING THREADS INDIVIDUALLY ISOLATED SUCH AS QUARTAS IN STAR (1A, 1B) AND BETWEEN TWO PARTS. OF MAINTENANCE AND HAVING A WIDTH (LR) INCLUDED BETWEEN ONE (D) AND TWO DIAMETERS OF THE THREADS (2A-5A, 2B-5B). The concave parties keep the quarters and the symmetry SEPARATED IN EACH PAIR OF THREADS AND ARE OBTAINED BY ADJUSTMENT OF A DEPRESSION IN THE HOSE DURING THE EXTRUSION.

Description

Power cable for high frequency with two driver groups

The present invention relates to a cable transmission for high frequency, telephone and / or signals teleinformatics and video (voice, data, images). The cable has substantially flat shape and comprises at least two groups of threads individually insulated electrical conductors surrounded by a collective maintenance wrap. Each group comprises at least a symmetrical pair of insulated electrical conductive wires, by example, a star quadrete consisting of two pairs of wires insulated conductors arranged at the apex of a square, the two conductor wires being isolated from the same pair arranged according to a diagonal of the square.

The relative positioning of the threads insulated conductors that form a star quad is essential to maintain a perfect symmetry of the square. Any defect of quadratic symmetry translates into parasitic couplings that entail transmission errors that cannot be corrected at depend on the flow of information transmitted in the quad.

European patent application EP 0642139 proposes a cable whose maintenance sheath is divided into two portions, surrounding each of the two groups of threads insulated electrical conductors The wrapper portions of maintenance are ajar facing each other along the cable so that they form two independent wrap tabs that they can be joined sensibly but not merged, or they can be put together and lightly adhere to each other, and they extend longitudinally between the two groups of conductive wires electrical insulated. The tabs delimit between them a throttling that has a width less than the diameter of the insulated electrical conductive wires. The objective intended by The characteristics of this known cable is to ensure an easy removal of the wrapper without any special cutting tool, for breakage, tearing or cutting of at least one of the tabs in order of opening the maintenance envelope and accessing the groups of insulated electrical conductive wires. In this cable, each group of insulated electrical conductive wires is a pair of conductive wires or comprises four freely arranged conductive wires, or mounted on tapes in two separate pairs.

European patent application EP 0642139 no addresses the maintenance of the symmetry of the conducting wires electrical insulators in at least two groups such as quadrets, and does not disclose any manufacturing process of the wrapping of maintenance.

The objective of the present invention is provide a maintenance wrap between at least two groups of insulated electrical conductive wires comprising pairs symmetrical, so that it maintains the symmetry in each pair and maintains a constant distance between the groups in order to attenuate all paradiaphony between them and preserve an impedance constant along the cable, while allowing a maintenance wrap manufacturing in one operation Extrusion

To this end, a high transmission cable frequency according to the invention comprising two groups of wires individually insulated electrical conductors and a wrapper maintenance that surrounds the whole and keeps separate longitudinally the two groups, is characterized by a narrowing that extends longitudinally between the two groups of conductors and between two concave longitudinal portions of the maintenance envelope, and it has a width between a diameter and two diameters of the threads insulated electrical conductors

The concave longitudinal portions of the maintenance wrap form a narrowing of it between the groups of insulated electrical conductive wires that keep a constant distance the groups and pushing these against the convex side portions of the maintenance wrap, what which prevents any movement of the groups towards each other. The narrowing width comprises between one and two diameters of insulated electrical conductive wires, maintaining a space relatively important between the two groups, which gives the sufficient flexibility cable during the different cable manipulations, for example, during manufacturing, the pulled or cable placement. The narrowing is obtained easily thanks to a single shell extrusion operation of maintenance, as is evident in the subsequent description of the Cable manufacturing process according to the invention.

Each cross section of each portion Concave longitudinal maintenance wrap is applied against one of the electrical conductor wires isolated in one of the groups, and one of the electrical conductor wires isolated in the another group located on both sides of the narrowing. The maintenance wrap, although it does not completely wrap every thread group, keeps it in place in a constant position in cross section relative to the other group of threads, which confers a very low level of paradiaphony.

In order to increase the isolation between groups, a flat, cylindrical longitudinal band, or with any another appropriate insulating material profile may be housed in the narrowing between groups of electrical conductive wires isolated and tight between the concave longitudinal portions of The maintenance wrap.

The cable may comprise a line of tear that extends between one of the side portions convex of the maintenance envelope and the respective group of insulated electrical conductive wires. The pull of one of the ends allows tearing the maintenance wrap during removal of it from one of the groups without necessarily withdrawing the Other group wrap.

An at least partially metallic shield It can surround the maintenance wrap, and a continuity thread electric and / or a tear wire can be extended between the two concave longitudinal portions of the envelope of maintenance and shielding, which gives an oval profile regulate the cable, despite the concave longitudinal portions of the maintenance wrap.

Each group of electrical conductive wires Isolated can be a star quadrete. More generally, more than two groups of insulated electrical conductive wires can be juxtaposed substantially along the envelope of maintenance and separated two by two by the narrowings, delimited each by two concave longitudinal portions respective of the maintenance envelope.

The invention also relates to a Manufacturing procedure of high power cable frequency of the invention, by means of an extruder comprising an inlet conduit coaxially extended by a conduit of a tubular punch that has an elongated front end and surrounded by a mouthpiece The procedure is characterized by guidance of the groups of electrical conductive wires isolated at the end front of the punch duct, to keep them juxtaposed in an axial plane with a predetermined separation corresponding to narrowing in the maintenance envelope, by aspiration created thanks to an extraction pumping means that communicates with the entrance duct to generate a depression in the envelope of extruded maintenance coming out of the nozzle in front of the end elongated front of the punch, and by an adjustment of the pumping means by extraction so that depression deforms the portions Longitudinal maintenance wrap between groups of insulated electrical conductive wires and lead them towards each other to a distance equal to the width of the narrowing to form the concave longitudinal portions.

The means of pump extraction procedure is set to a suction pressure included between approximately 10 2 and 10 5 pascals, so that the narrowing has a width between one and two wire diameters, for a cable that has a thickness of some millimeters

The cross sections at the ends front of the punch and nozzle ducts may have similar and significantly larger oblong or elliptical profiles that the contour of the maintenance wrap, what you need a less deep depression than with the nozzle ends and punch classically cylindrical, but to the detriment of a tooling of more specialized extruder.

When an insulating loop is provided that forms partition between two groups, the procedure includes a guide of a flat, cylindrical longitudinal band, or with any other appropriate profile of insulating material between the groups of wires insulated electrical conductors in the punch duct and a squeeze the band through the concave longitudinal portions of the maintenance wrap carried towards each other by the depression.

Other features and advantages of this invention will become more apparent upon reading the following description of several preferred embodiments of the invention with reference to the corresponding annexed drawings, in which:

- Figure 1 is a cross section of a two quad cable according to a preferred embodiment of the invention;

- Figure 2 is a cross section of a two quad cable according to another embodiment of the invention;

- Figure 3 is an axial sectional view of a head-to-square extruder to extrude the envelope of cable maintenance following figure 1 or 2;

- Figure 4 is an axial section view more detailed schematic of the nozzle and the front end of the punch in the extruder of figure 3;

- Figure 5 is a schematic front view of the cylindrical front face of the nozzle and the punch in the part front of the extruder;

- Figure 6 is a schematic front view of the oblong front face of the nozzle and punch in the part front of the extruder, according to another embodiment; Y

- Figure 7 is a cross section of the cable according to figure 1 completed by a screening of shielding and an outer protective wrap.

According to the embodiment illustrated in Figure 1, a CA1 high frequency transmission cable comprises two groups 1a and 1b of individually insulated electrical conductor wires. In which follows from the description, similar elements or elements relating to similar elements in the two groups 1a and 1b are designate by the same numerical references followed by the letter a and b, respectively.

Each group 1a, 1b of conductive wires is a quadrete in twisted star composed of four wires Electrical conductors 2a to 5a, 2b to 5b individually insulated. Each insulated electrical conductor wire consists of a solid conductor or a twisted cable of fine copper wires 6 annealing and an individual insulating liner 7 surrounding the 6 solid conductor, for example, of polyethylene or polypropylene solid, or cellular, or cellular and solid. Seen in cross section, the four electrical conductor wires 2a to 4a, 2b to 4b insulated in a square 1a, 1b are arranged at the vertices of a square, and they are symmetrical two to two in relation to the axes and the diagonals of any square of cross section along of the laces of the quad, so that any defect of quadratic symmetry that could induce couplings parasites

The maintenance cable CA1 comprises, also, a thin insulating maintenance wrap 8 that surround the two squares 1a and 1b together. The envelope of maintenance 8 is made of an extruded thermoplastic material according to the method of the invention, the thermoplastic material being, preferably transparent so that the different colors of the 7 individual thread coverings insulated conductors in each of the two quadrets. For example, The maintenance wrap has a thickness between 0.1 and 1 mm. The thermoplastic material of the maintenance wrap, such as for example polyethylene, polypropylene or PVC, It has a reduced dielectric constant and characteristics sufficient mechanics to ensure the maintenance of qualities and flexibility of the cable.

Cross-sectional view as shown in the Figure 1, the maintenance wrap 8 of the CA1 cable is symmetrical in relation to a medium longitudinal plane YY that passes between the two quadrats 1a and 1b and dividing the envelope into two portions 81a and 81b that are substantially horseshoe-shaped whose ends are together two to two. The pairs of joined ends of the portions of the maintenance envelope 81a and 81b constitute two portions 82 and 83 longitudinal centrals that are concave, that is to say they have symmetrical convex internal surfaces with respect to another in relation to a longitudinal plane that has the XX path in figure 1, perpendicular to the YY plane, and passing through the axes central of the two quadrets.

A space 84 located inside the wrap 8 between the two squares 1a and 1b constitutes a narrowing in relation to the thickness E of the portions of the maintenance wrap 81a and 81b that surrounds only partial, respectively, squares 1a and 1b; indeed, the Portions of individual wrappers 7 of two conductive wires Adjacent 2nd and 3rd of Quad 1a and two conductive wires 2b and Adjacent 3b of quad 1b are directly facing two to two and separated by narrowing 84. Each portion 81a, 81b of the maintenance wrap partially surrounds the square 1a, 1b respective, without the conductive wires 2a to 5a, 2b to 5b isolated are housed in maintenance wrap portion 81a, 81b respective.

As will be seen in the manufacturing procedure according to the invention, the curved wrap portions 82 and 83 Concave are obtained by hot "stretching" the material thermoplastic extruded from the maintenance wrap, in order to that each wrap portion 82, 83 be constantly applied against an electric conductor wire isolated from the first quad 1a, in this case the conductive wire 2a, 3a insulated according to the cut of the CA1 cable illustrated in Figure 1, and against a conductive wire electric insulated from the second quad 1b, in this case the wire electrical conductor 2b, 3b insulated according to the CA1 cable cut illustrated in figure 1. When each square is twisted, each insulated electrical conductor wire occupies in cross sections successive quadrente a position that rotates progressively around the center of the quad when it travels along the axis of a quad cord. The 82 and 83 concave portions of the maintenance wrap are in contact successively, by for example, with the electrical conductive wires 2a and 3a, in addition to 3a and 4th, in addition to 4th and 5th and finally 5th and 2nd, and so on in each period of twisting in square 1a, as far as the that the direction of the cords is not modified. Portions 81a and 81b in horseshoe of maintenance wrap 8 are in contact with the other two conductors in the squares 1a and 1b respective, in this case the conductive wires 4a and 5a isolated in the first quad 1 and the conductive wires 4b and 5b isolated in the second quad 1b, according to the cross section of the cable CA1 shown in figure 1.

The narrowing 84 has a width LR between a diameter D and two 2D diameters of the wires Electrical conductors 2a to 5a, 2b to 5b insulated. For example, according to the embodiment shown in figure 1, the width LR of the narrowing 84 is approximately 1.7D, while according to a second embodiment shown in Figure 2, the narrowing 84 It has a width of 1.2D. The width LR of the narrowing 84 is choose depending on the use and cost of the cable.

The narrower the narrowing 84, the more the squares 1a and 1b will be kept separated and higher will be a suction pressure applied to the extrusion casing, according to the process of the invention and therefore more difficult will be make the narrowing; however, tensile forces exercised laterally in opposition to the wrap portions 82 and 83 concave to stretch them will be so much higher the more small be the width LR of narrowing 84 and thicker be 82 and 83 wrap portions. On the contrary, during operation of removing the wrap, the larger the width LR of narrowing 84 and the thinner portions 82 and 83 of wrapping, the extraction of one end of the square 1a, 1b through the horseshoe opening of portion 81a, 81b between the 82 and 83 concave portions, if any after an incision or start by cutting one or two 82 and 83 concave portions. The CA1 cable shown in Figure 1 it presents a removal of the wrap of the quadrines easier than that of the CA2 cable shown in Figure 2. However, the CA2 cable it has 82 and 83 concave wrap portions whose surfaces internal, by comparison, are more pointed in the direction of center of the wrap such that portions 82 and 83 concave have internal application surfaces against the conductive wires 2a, 3a, 2b and 3b larger insulated and therefore exert a higher separation effort from the two quadr

The cables of the invention are, for example, substantially flat, that is, with an oval cross section or elliptical or oblong in which two quadrants or more are juxtaposed. They are used, in particular, as telephone transmission cables and / or teleinformatics and / or video for building wiring. Every quad star 1a, 1b comprises two pairs of conductive wires insulated, each pair comprising two insulated conductive wires arranged following a diagonal of the square section of the quad. However, the invention is not limited to cables in quadr For example, the two groups of insulated conductive wires can each comprise more than two pairs of conductive wires electrical insulated, although groups can present numbers different from insulated conductive wires.

According to another example, the cable comprises more than two groups of insulated conductive wires; generally when a cable It comprises N groups of insulated conductive wires, N being a number integer, the cable has (N-1) strangulations 84 between groups taken successively two to two. According to others variants, the cable can be a mixed cable, with at least one of groups that do not include more than optical conductors, such as optical fibers, protected individually or together, and / or with one of the groups that includes, at the same time, conductive wires individually insulated electrical and wrapped optical conductors individually.

According to a variant, a cable of the invention it comprises three or four quadrets or more arranged in star in cross section.

With reference to figure 3, the two quadrets 1a and 1b are pulled, for example, through holes in one or several guide plates from two twisted quad reels followed by throwing drums, or from two parallel positions of quadrill manufacturing to penetrate continuously following the arrow F through an inlet duct 10 of an extruder EX from head to toe.

The EX extruder shown in Figures 3, 4 and 5 classically comprises a cylindrical punch 11 of the tube type which is extends along the main longitudinal axis of the head of extrusion, and an extrusion screw 12 arranged perpendicular to the punch 11. The extrusion screw 12 pushes the softened thermoplastic material, such as polyethylene, in the conduits 14 to the front periphery of the punch 11. At one end exiting the extruder, a nozzle 15 of the tube type has a anima 16 conical trunk whose small base is prolonged by a hole 17 front. The bore 16 conical and the hole 17 surround coaxially and substantially complementary way a Conical trunk portion 18 and a revolution portion 19 of the end front of the punch.

To make the cable of the invention, the cross sections of the hole 17 of the nozzle and the 19 revolution portion at the front end of the punch can be cylindrical, as shown in figures 4 and 5. Both quadrats 1a and 1b after having penetrated the duct of inlet 10, cross a long axial duct 20 of the punch 11 which progressively narrows to the level of the front end of the punch 18-19. The circular sections of the bore front 17 of the nozzle 15 and the front end 19 of the punch 11 have internal and external diameters significantly higher than larger internal LI and external LE dimensions (figure 1) of the wrap 8 to get, respectively. Quadrats 1a and 1b they pass, respectively, the holes 21 in a guide 22 fixed transversely to the outlet of conduit 20, so that it maintains quadrats 1a and 1b juxtaposed in an axial plane, for their definitive separation in the maintenance envelope 8 at the exit of the extruder. More generally, when the cable to be manufactured must contain N groups of wires, guide 22 contains N holes 21 juxtaposed in an axial plane to the punch, two to two distant from the definitive separation of the groups in the cable at the level of the N-1 narrowings of the envelope maintenance.

The extrusion material pushed between the nozzle 15 and the front end 18-19 of the punch 11 continuously form, first, a wrap with a profile Conical trunk around the set of the two quadrants 1a and 1b. This conical trunk wrap at the exit of the EX extruder tends, naturally, to stick on the lateral periphery of the quadr at the level of portions 81a and 81b in horseshoe and sink to YY axis length to move to a diameter smaller than the dimension external LE larger (figure 1), but greater than the thickness E of the wrap 8 to be obtained, subject to cooling of the wrap extruded into a cooling box at the exit of the extruder FORMER.

According to the invention, the narrowing 84 is created by a DE depression inside the envelope 8 that comes out of the nozzle 15 and mainly in the center of it, between the two squares 1a and 1b. DE depression is generated by the suction of a vacuum pump connected to a pipe 23 of vacuum that flows into the inlet duct 10 of the head of extrusion, in front of a sealing ring 24 crossed by the squares 1a and 1b that come from the coils or the posts of manufacturing. Regulating the suction pressure of the pump empty, DE depression is more or less elevated in the duct 20 longitudinal of the punch, and particularly at the level of the end front 19 of the punch, from which the two quadrants 1a and 1b come out. This front end of the punch protrudes a few millimeters from the front face of the nozzle, so that the material hot thermoplastic does not immediately contact the quadrines and start sinking naturally around the whole of quadrets.

The lower the DE depression, the less deforms the envelope 8. For example, a DE depression of some thousands of pascals stretches towards the center of the envelope the central portions, substantially convex circular to be progressively deformed in concave 82 and 83 portions of a cable, as shown in figure 1; a depression of the order of 10,000 pascals stretches portions 82 and more substantially 83 concave, so that you get a wrap of maintenance, as shown in figure 2.

According to another embodiment shown in Figure 6, the tooling at the exit of the extruder is a bit modified. The cross sections of conduit 200 in front of the punch and the revolution 170 front portion of the nozzle present oblong or elliptical profiles significantly larger than the Oblong profile PO of the maintenance wrap 8 to obtain, without Concave portions 82 and 84, as shown in Figure 1.

The DE depression necessary for deformation by stretched portions 82 and 83 concave to approximate, according to this other embodiment is less elevated than with the tooling shown in figure 5.

As a variant, a longitudinal band 24 thin consolidation thermoplastic separator, as shown with dotted lines in figure 2, it is sandwiched between the quadrats 1a and 1b perpendicular to portions 82 and 83 Concave maintenance wrap. The height of the band 24 is at least equal to the width LR of the narrowing 84, but It has a thickness less than the distance between the two squares. During the manufacture of the cable according to this variant, the band 24 thin that forms a partition between the two quadrants 1a and 1b is thrown continuously between them and crosses a rectangular hole 25 disposed between the circular holes 21 in the guide 22 as shown in figure 6. At the exit of the EX extruder, the band of separation 24 is maintained between the two squares 1a and 1b by tightening and adhesion exerted by the concave portions 82 and 83 of The maintenance wrap.The band can be flat or cylindrical, or presents an appropriate profile for the space between the squares 1a and 1b.

The cable of the invention contains, in the practice, the following elements, as shown in the figure 7:

- a tearing end 26a or 26b for two quadrets, or two tear ends 26a and 26b, respectively, for the two quadrants 1a and 1b; being a cape of tearing 26a, 26b preferably located between the bottom of the respective convex side portion 81a, 81b of the envelope of maintenance 8 and the respective square 1a, 1b, in order to remove the quadrature wrap;

- an armor shield 27 having the minus a metallized face and surrounding the maintenance wrap 8, for example by curb;

- one or two continuity wires 28 and 29 electric placed in small longitudinal volumes between the shielding shield 27 and concave portions 82 and 83 of the maintenance wrap, which gives an oblong profile regulate the shielding and, as a consequence, the cable; a cape tearing can be placed with each thread 28, 29 of electrical continuity in said small longitudinal volume respective; Y

- an outer protective sheath 30 that surrounds the metallic shield 27, of insulating material such as PVC, or halogen-free flame retardant material.

Claims (11)

1. High-frequency transmission cable, comprising two groups (1a, 1b) of individually insulated electrical conductive wires (2a-5a, 2b-5b) and a maintenance envelope (8) that surrounds the assembly and keeps the cables separated longitudinally two groups, characterized by a narrowing (84) that extends longitudinally between the two groups (1a, 1b) of conductors and between two concave longitudinal portions (82, 83) of the maintenance envelope (8), and has a width ( LR) between a diameter (D) and two diameters (2D) of the electrical conductive wires (2a-5a, 2b-5b) isolated. 2. Cable according to claim 1, in which each cross section of each portion (82, 83) Concave longitudinal maintenance wrap (8) is applied against one (2nd, 3rd) of the electric conductive wires isolated in one (1a) of the groups and against one (2b, 3b) of the electrical conductive wires insulated in the other group (1b), located on both sides of the narrowing (84). 3. Cable according to claim 1 or 2, comprising a longitudinal band (24) of insulating material housed in the narrowing (83) between the groups (1a, 1b) of threads electrical conductors insulated and tight between the portions (82, 83) concave longitudinal maintenance wrap (8). 4. Cable according to any one of the claims 1 to 3, which comprises a tearing rope (26a; 26b) that extends between one of the portions (81a, 81b) convex sides of the maintenance wrap (8) and the group (1a, 1b) respectively of insulated electrical conductive wires. 5. Cable according to any one of the claims 1 to 4, comprising a shield (27) to the less partially metallic surrounding the maintenance envelope (8) and a wire (28) of electrical continuity and / or a line of tearing (26a; 26b) that extends between the two portions (82, 83) Concave longitudinal maintenance wrap (8) and shielding (27). 6. Cable according to any one of the claims 1 to 5, wherein each group of conductive wires Electrical insulated is a quad (1a, 1b) in star. 7. Cable according to any one of the claims 1 to 6, comprising more than two groups (1a, 1b) of insulated electrical conductive wires juxtaposed substantially to along the maintenance envelope (8) and separated two by two by narrowings (84), each delimited by two portions (82, 83) respective concave longitudinal envelopes of maintenance (8). Method of manufacturing the high frequency transmission cable according to any one of claims 1 to 7, by means of an extruder (EX) comprising an inlet conduit (10) coaxially extended by a conduit (20) of a tubular punch (11) having an elongated front end (18-19) and surrounded by a nozzle (15), characterized by a guide (21, 22) of the groups (1a, 1b) of electrical conductive wires isolated in the front end of the conduit (20) of the punch (11) to keep them juxtaposed in an axial plane, with a predetermined separation corresponding to the narrowing (84) in the maintenance envelope (8), by an aspiration created thanks to a means of extraction by pumping (23) that communicates with the inlet duct (10) to generate a depression in the extruded maintenance envelope (8) that exits through the nozzle (15) in front of the elongated front end (18-19) of the punch, and by a me setting He gave pump extraction (23) so that the depression (DE) deforms the longitudinal portions of the maintenance envelope (8) between the groups (1a, 1b) of insulated electric conductive wires and takes them towards each other at an equal distance to the width (LR) of the narrowing (84) to form the concave longitudinal portions (82, 83). 9. Procedure according to claim 8, according to which the pumping extraction means (23) is adjusted to a suction pressure between 10 2 and Approximately 10 5 pascals. 10. Procedure in accordance with the claim 8 or 9, according to which the cross sections in the front ends of the ducts (200, 170) of the punch (11) and of the nozzle (15) have similar oblong or elliptical profiles and significantly larger than the envelope contour of maintenance (8). 11. Procedure according to any one of claims 8 to 10, comprising a guide (25) of a longitudinal band (24) of insulating material between the groups of wires (1a, 1b) insulated electrical conductors in the conduit (20) of the punch (11) and a tightening of the band (24) by the portions (82, 83) Concave longitudinal maintenance wrap (8) taken towards each other by depression.